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Steve Bannon found himself back in the hot seat last month as the former White House adviser answered questions from Senate intelligence committee investigators behind closed doors, according to two sources familiar with the meeting. The sources said investigators asked about Cambridge Analytica, the controversial and now-defunct data firm he co-founded; and Roger Stone, a self-described dirty-trickster and Trump associate.

The committee has been quietly investigating Russian meddling in the American political system for nearly two years. While partisan acrimony rocked the House intelligence committee’s Russia probe, the Senate’s investigation has proceeded with scant public friction.

Spokespeople for Senate Intelligence Committee Chairman Richard Burr and Vice Chairman Mark Warner declined to comment on the record. A lawyer for Bannon declined to comment on the record as well.

Bannon’s interview indicates investigators remain interested in Cambridge Analytica’s work for President Donald Trump’s 2016 campaign. The firm’s staff claimed it used “psychographic profiling” to tailor ads based on people’s personality traits. The firm’s critics said this was bluster, and drew comparisons to failed blood-testing start-up Theranos.

Cambridge Analytica drew international opprobrium when its work covertly harvesting millions of Facebook users’ personal information was revealed in March. Facebook denounced the company’s tactics, but still suffered enormous public blowback. In May, Cambridge Analytica announced it was closing down.

Bannon had close connections to the firm. His former patron, heiress Rebekah Mercer, was on its board and also helped fund Breitbart. And while Trumpworld figures like Paul Manafort had a low view of the firm, Cambridge Analytica whistle-blower Christopher Wylie told CNN that the company was “Bannon’s arsenal of weaponry to wage a culture war on America using military strategies.”

The interview also indicates the committee is interested in Stone, a longtime Republican operative famous for unethical practices. During the 2016 campaign, Stone made eerily prescient comments about the WikiLeaks document dumps. Investigators working for special counsel Robert Mueller have interviewed many witnesses about potential connections between Stone and WikiLeaks founder Assange. Senate investigators, it appears, share those questions.

Since leaving the White House in August 2017, Bannon’s political cachet has withered. The book Fire and Fury: Inside the Trump White House quoted him making a host of disparaging comments about his White House colleagues, and Trump personally denounced him. Mercer, his former benefactor, knifed him as well.

Bannon’s comments in the book—including a suggestion that Don Jr. may have introduced Kremlin operatives to his father—appear to have even attracted the attention of Mueller. Before the book’s publication, according to a source familiar with his probe, he hadn’t indicated interest in Bannon. After it was published, Mueller subpoenaed the former Trump campaign boss, who went on to have several meetings with the special counsel’s team.

Bannon also damaged relationships with Washington Republican power-brokers by backing the Senate campaign of accused child molester Roy Moore. Bannon helped Moore beat a more moderate Republican in the Alabama Senate primary, but Moore lost the race to Democrat Doug Jones.

So while Trumpworld may be over Bannon, Russia investigators clearly are not.